1. Field of the Invention
This invention relates to apparatus for reducing the wobble in a rotating shaft and, more specifically, to an improved device for minimizing spindle wobble caused by spurious or undesirable positionings of a bearing assembly rotatably supporting the spindle.
2. Description of the Prior Art
Disk drives are widely used as peripheral memory storage systems for computers. Such systems typically include a rotating spindle upon which is mounted a hub with magnetic disks stacked thereon in a spaced array. The rotating spindle has a tendency to wobble due to manufacturing tolerances and clearances involved in making the bearing assemblies which rotatably support the spindle. Such wobble is undesirable because it limits the data storage capacity of the magnetic disks.
Prior art apparatus solved the wobble problem in great measure by spring loading a movable section of the bearing assembly so that radial forces are generated and applied to the rotating spindle thereby overcoming the tendency of the spindle to wobble. Spring loading is well known in the prior art and is also called preloading. However, spring loading of the bearing assembly has resulted very often in the undesirable positioning (cocking positioning) of the bearing assembly which in and of itself has caused the spindle to wobble.
The present invention reduces the incidence of mispositioning and thereby further aids the spring loading technique to reduce spindle wobble.